[NET]: Fix TX timeout regression in Intel drivers.

This fixes a regression added by changeset
53e52c729cc169db82a6105fac7a166e10c2ec36 ("[NET]: Make ->poll()
breakout consistent in Intel ethernet drivers.")

As pointed out by Jesse Brandeburg, for three of the drivers edited
above there is breakout logic in the *_clean_tx_irq() code to prevent
running TX reclaim forever.  If this occurs, we have to elide NAPI
poll completion or else those TX events will never be serviced.

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Jesse Brandeburg <jesse.brandeburg@intel.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
index 13d57b0a88fa..0c9a6f7104d2 100644
--- a/drivers/net/e1000/e1000_main.c
+++ b/drivers/net/e1000/e1000_main.c
@@ -3919,7 +3919,7 @@ e1000_clean(struct napi_struct *napi, int budget)
 {
         struct e1000_adapter *adapter = container_of(napi, struct e1000_adapter, napi);
         struct net_device *poll_dev = adapter->netdev;
-        int work_done = 0;
+        int tx_cleaned = 0, work_done = 0;
 
         /* Must NOT use netdev_priv macro here. */
         adapter = poll_dev->priv;
@@ -3929,14 +3929,17 @@ e1000_clean(struct napi_struct *napi, int budget)
          * simultaneously.  A failure obtaining the lock means
          * tx_ring[0] is currently being cleaned anyway. */
         if (spin_trylock(&adapter->tx_queue_lock)) {
-                e1000_clean_tx_irq(adapter,
-                                   &adapter->tx_ring[0]);
+                tx_cleaned = e1000_clean_tx_irq(adapter,
+                                                &adapter->tx_ring[0]);
                 spin_unlock(&adapter->tx_queue_lock);
         }
 
         adapter->clean_rx(adapter, &adapter->rx_ring[0],
                           &work_done, budget);
 
+        if (tx_cleaned)
+                work_done = budget;
+
         /* If budget not fully consumed, exit the polling mode */
         if (work_done < budget) {
                 if (likely(adapter->itr_setting & 3))